Discharge valve assembly for fuel injector pumps



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G. W. BAIERLEIN DISCHARGE VALVE ASSEMBLY FOR FUEL INJECTOR PUMPSoriginal Filed Feb. 27,l 194s Nov. 3G, 1948.

Patented Nov.r 30,l 1948 DISCHARGE VALVE ASSEMBLY FOR FUEL INJECTOBPUMPS George W. Baierlein, Springfieid,-Mass.,

assigner to Niles-Bement-Pond Company, West Hartford, Conn., acorporation oi' New Jersey original application Februar-62.*?, 194s,serial No.

650,408. Divided and this application February 6, 1947, Serial No.726,846. v

The present application is a division of my application Serial No.650,408, illed February 27, 1946.

The present invention relates to fuel injection pumps for internalcombustion engines. Certain of 'the features of the invention are ofparticular utility in connection with a pump for a multiple cylinderengine having a plurality of pump plungers, one for each cylinder. Otherfeatures of the invention are of especial utility in connection with aninjection pump adapted for use on an aircraft engine, wherein lightweight is very important.

An object of the present invention is to provide an improved pump barreland discharge valve assembly for use in a pump of the type described:

Other objects and advantages of the present invention will becomeapparent from a consideration of the appended specification, claims anddrawings, in which The figure is a view, partly in cross-section, of amultiple plunger fuel injection pump and embodying my invention.

Referring now to the drawings, there is shown a pump mechanismconsisting of a mounting plate I8, which is provided with a iange l2,having holes I4 bored through it to receive bolts (not shown) so that itmay be mounted on a suitable pad provided on an internal combustionengine. A pump body I6 is attached, by any suitable means such as dowelstuds, (not shown), to the mounting plate I0. A drive shaft 28 iscarried in the plate I by a combined radial and thrust ball bearing 22and by a needle bearing 24 in the body I6.

On the lower side, as it appears in the drawings, of the body I6, theshaft 28 carries, thru a combined thrust and radial bearing 26, a wobbleplate 28. The wobble plate 28 actuates, thru mechanism to be describedin detail.below,.a plurality of pump plungers 30, which reciprocate inbarrels 32 received in bores 24 thru the housing I6. A cover 36 isprovided for the pump. This cover is attached, by means of bolts anddowel pins (not shown) to the pump body I6.

'I'he end of pump barrel 32 nearest the plate I0 is closed by a valveseat member 42. This seat member is provided with a passage thru itscentral portion, and a valve 44 engages the face of the seat member onthe side opposite the barrel 32. A spring 46 biases the valve 44 toclosed position. The spring 46 is held by a retainer 48 threaded intothe plate I8. and a spacer 54 separate the -rim of the retainer 48 fromthe rim of seat member 42. When the Washers 56 and 52- 2 Claims. (Cl.103-l54) with a suitable central aperture to retainer 48 is threaded inplace, it holds the washers 56 and 62, the spacer 54, the seat member42, and the barrel 32 in assembled relation, forcing a shoulder 58 onthe barrel 32 up against a corresponding shoulder in the pump body I6-The spacer 52 is provided with lateral outlet passages 58, leading to adrilled passage 68 which opens into the bolt hole I4. From there thefuel discharged by the pump may be conveyed thru a hollow bolt, in awell-known manner, to one of the cylinders of the engine.

The outer'surface of each of the barrels 32 is provided with a recess33., A set screw 85, carried by the body I6 engages the recess 88 andholds the barrel against rotation in the body I6, so that thecalibration of the pump cannot be disturbed by any change in the angularposition of port |34. v

The outer race of bearing 22 is press-fitted into the plate I6. Theinner race is held against a shoulder on the shaft 28 by a lock nut 62and a lock washer 64. It may be seen that the thrust forces on thebearing 22 are suchas to tend to move the shaft 2U downwardly thru theplate l 8. Therbefore these-thrust-forces tend to hold the outer` raceof bearing 22 more rmly in its seat.

The inner race of bearing 26 is held in place against a shoulder onshaft 20 by a lock nut 66 and a lock washer 68. A timing disc 18 isclamped between the lock washer 68 and the inner race of bearing 26. Thepurpose of the timing disc 10 will be later described. The outer racevof the bearing 26 isretained in the -wobble plate 28 by a retainingring 12, which may be of the wellknown snap ring type.

Each of `the plungers 30 is connected by means of a shear pin 14 to aVpush rod 16. The lower end of push rod 16 terminates in a ball 18. Thewobble plate 28 is provided on its peripheral surface with a groove 80,Wide and deep enough to receive the balls 18. The groove separates anupper, as it appears in the drawing, flange 82 on the wobble plate froma lower ange 84. The upper flange 82 has its'outer edge slotted, as at86, so that the push 'rods 16 may be lpassed thru the slot duringassembly. Each of the slots 86 opens into a generally circular aperture88, which allows for the wobbllng motion of the wobble plate 28 withrespect to the'push rods 16. Each of the balls 18 rides in a pair ofupper and lower shoes 90 and 92, which are received with the ball in thegroove 80. The upper shoe 96 is provided permit passage of the push rod16 therethru. It may be seen that as the shaft 20 rotates a wobblingmoers 30 and push rods 18 are sequentially reciprocated. It may also beseen that the thrust forces acting parallel to the shaft 20, due to theiiuid pressures built up by the plungers, are all carried by theplungers 30, the associated structure which connects the plungers to thewobble plate, the` wobble plate 28, and shaft 20 to the bearing 22 andthe mounting plate I0. The body i6 is fixed at one end to the mountingplate |0. No other part oi the body I6 is attached to any xed part ofthe engine. Thrust forces reaching the plate I are not transmitted thruthe body I6, because there can be no opposing reactive force. Hence thebody i6 cannot be stressed by such thrust forces. Therefore, it ispossible to build the body I6 of a light, relatively weak metal such asaluminum, while^the parts subject to' stress are made of stronger metal,such as steel. In this way it has been found possible to substantiallyreduce the weight of the multiple pump unit. Where .such a pump unit isintended for use in an aircraft, such a reduction in weight istremendously important. It should be noted that the flange 82, whichtransmits thrust to the plungers on their intake strokes, is madelighter than the flange 84, which transmits thrust to the plungers ontheir pumping strokes. This difference in the thickness of the twoiianges also contributes to the reduction of the weight of my pumpingmechanism.

Each plunger 30, carries a sleeve 94, which includes a generally tubularportion 96. The portion 86 is slotted'as shown at 98 from one sidelaterally across for a distance of more than half its diameter. The partof the sleeve 94 below the slot 98 is provided with a longitudinal slotas shown at |00, which separates t t portion of sleeve 96 into twoiingers which a e provided at their free ends with lugs |06, |08respectively.

A tapered screw i|0 is provided for joining the two lugs. It may be seenthat upon tightening of the screw H0, lugs |06 and |08 are drawntogether and nthe two iingers are tightly clamped on the surface of thepush rod 16, so that the sleeve 94 and the push rod 16. and the plunger30 rotate together. When the screw ||0 is loosened, it is possible torotate the push rod 16 within the sleeve 94 without rotating the latter.sleeve 94 is provided with a pair of upwardly extending projections ||2which mate with corresponding projections ||4 on a sleeve l|6 whichsurrounds the barrel 32. The sleeve ||6 carries a pinion gear ||8 havingteeth over at least a 90 sector thereof. All of the pinion gears ||8engage a central ring gear carried on a projection hub portion of thepump body |'6. The toothed portions of the pinion gears ||8 all faceinwardly so as to engage the ring gear |20.

One of the sleeves ||6 is also provided, on the portion of its peripherynearest the outside of the casing, with a bevel gear sector |22. Thisengages with another bevel gear sector |24 carried by a control shaft|26 mounted in a suitable hub |28, which is carried by the pump body |6.Out-side the body |6, the control shaft |26 is splined, as shown at |30and thereby provided with means by which it may be rotated from theoutside of the pump unit. f

Each of the pump plungers is provided with a helical scroll |32 ofgenerally conventional form, which cooperates with aninlet port |34.When the port |34 is closed by the scroll |32, then the plunger isactively pumping fuel thru the dis- The' charge valve 44.Y Each plungeris also provided. below the scroll |32, with a circumferential groove|33. As soon as the port |34 is uncovered by the upper edge of groove|33, then the pressure ahead of the plunger is relieved and pumpingceases. By rotating the plunger on its own axis, the length of theperiod during which pumping takes place may he varied, thereby varyingthe fuel delivery per stroke of the pump plunger. By operation of thecontrol shaft |26, all the plungers may be simultaneously rotated.Rotation of control `shaft |26 causes one pinion gear H0 to be rotatedand this motion is transmitted thru the ring gear |20 to all the otherpinion gears. If it is desired to adiust the delivery per stroke oi oneof the plungers, without aiiecting the others, it is only necessary toremove the cover 36 whereupon the clamping screws ||0 associated withall the plungers become accessible.

The timing disc 10 cooperates with a timing pin |36 s o that itispossible to determine the angular position of the pump shaft from theoutside of the casing. The periphery of the disc l0 is slotted as shownat |38. The timing pin |36 is mounted in a cup |40 carried by the cover36. A spring |42 in the cup |40 biases the pin to the position shown inthe drawing where it does not engage the slot |38 or the timing disc 40.A cover |44 is provided for the outer end of the timing pin so that itwill not be accidentally pushed in while the pump is in operation. Whenit is desired to determine the angular position of shaft 20 for timingthe pump to the engine, the cover |44 is removed and the pin |36 isdepressed and held in. The shaft 20 may then be slowly rotated by handuntil the pin is felt to drop into the yslot |38. The slot |38 islocated in the timing disc 10 so that its angular position correspondsto the end of delivery by the pump plunger serving cylinder No. 1 ci theengine.

The driving end of shaft 20 is driven thru an intermediate drive member|46, which corrects for misalignment between the pump shaft 20 and theengine drive shaft. 1

The shaft |26, outside the body I6 may be provided with a suitablepointer |60 cooperating with a scale |62L to indicate the pump deliverysetting.

Fuel is supplied to the pump thru an inlet connection (not shown) whichleads to a chamber |56 surrounding all the barrels 32 at a point neartheir inlet ports |34.

Oil is supplied under pressure through a connection (not shown) to thechamber |60 formed between the cover |56 and the pump body ||6. The oilows from the chamber |60 thru a check valve |62 and thence out thru thehollow center of the shaft 20. This lubricating system is completelyshown and claimed in the copending application of Milton E. Chandler,Serial No. 609,350, iiled August '7, 1945, which has mashoulder on saidbody within said bore. a barrel receivable in said bore and having ashoulder l adapted toengage the shoulder` in said bore, a

recess in an external face of said barrel, a set screw insertable thrusaid body to engage said recess and hold said barrel against rotation, aplunger reciprocable in said barrel, a discharge valve seat member insaid bore engaging the end of said barrel, a valve member engaging theface of said seat member opposite said barrel, hollow spacer means insaid bore engaging said seat and surrounding said valve, a springretainer threadedly inserted in said bore and engaging said spacer meansto hold said spacer means, said seat member and said barrel in assembledrelation, and a spring within said spacer and retained by saidretainerand biasing said valve to closed position, said spacer being laterallyapertured to permit outow of iuid passed by said valve.

2. Injection pump mechanism, comprising a generally cylindrical housingincluding a mounting plate and a body attached to said plate, said bodyhaving a plurality of bores extending therethru from said plate parallelto the axis ciy said housing, a shoulder on said body within each saidbore, said plate having a plurality of bores alined with the bores insaid body, a barrel receivable in each said bore and having a shoulderadapted to engage the shoulder in said bore, said barrels being longerthan said body so as to extend within said plate when said shoulders arein engagement, a recess in an external face of each said barrel, a setscrew insertable thru said body to engage said recess and hold saidbarrel against rotation, a plunger reciprocable in each said barrel, adischarge valve seat member in each of said. plate bores engaging theend of said barrel, a valve member engaging the face of said seat memberopposite said barrel, hollow spacer means in each said plate boreengaging said seat and surrounding said valve, a spring retainerthreadedly inserted in each said plate bore and engaging said spacermeans to hold said spacer means, said seat member and said barrel inassembled relation. and a spring within said spacer and retained by saidretainer and biasing said valve to closed position, saidv spacer andplate being laterally apertured to permit outflow of iiuid passed bysaid valve.

GEORGE w. BAIERLEINQ REFERENCES crrsn The following references are ofrecord in the file of this patent:

UNITED STATES A'rENTs

